1 / 45

Joe Ramey

2013-2014 Winter Outlook for the Mountain Valleys of Colorado Uh Oh… No Ni ño Again!. Joe Ramey. not quite El Ni ño. La Ni ña. National Weather Service Grand Junction. Outline. Background information - - An Overview of CPC’s Seasonal Outlooks

colm
Télécharger la présentation

Joe Ramey

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 2013-2014 Winter Outlook for the Mountain Valleys of Colorado Uh Oh… No Niño Again! Joe Ramey not quite El Niño La Niña National Weather Service Grand Junction

  2. Outline Background information - -An Overview of CPC’s Seasonal Outlooks - Describe El Niño Southern Oscillation (ENSO), - Pacific Decadal Oscillation (PDO) - Trends Analysis Last winter – compare the outlook and results - a Neutral ENSO season Outlook for this Winter – Neutral ENSO- Downscale snowfall patterns for ENSO Neutral seasons for Steamboat Springs, Winter Park, Breckenridge, Aspen since 1980, Crested Butte, Telluride up to 2008, Silverton

  3. Climate Prediction Center’s Outlook For December-January-February 2013-2014 Temperature Precipitation

  4. Climate Prediction Center’s Outlook For December-January-February 2010-2011 Dart Board Analogy

  5. CPC Seasonal Forecast Tools El Niño-Southern Oscillation (ENSO) Long-Term Trends - weighted to the most recent 15 years Other Statistical Models: Canonical Correlation Analysis (CCA) , Screened Multiple Linear Regression (SMLR), Constructed Analysis (CAS) Dynamical Models: Coupled GCM, Ensembles Tool Consolidation (OCN, CCA, SMLR, CFS, ECCA) Mike Halpert, CPC, Operational Climate Conference June 2010

  6. 1983-84 1992-93 (an ENSO Neutral Season) 2012-13

  7. What determines whether we will have awet or dry cold season? • The Answer: Storm track and storm intensity • Beyond the seven day forecast, long-range forecasters look to the state of the oceans for clues to storm track and intensity • The main ocean pattern or oscillation that is used for cold season outlooks: • El Niño Southern Oscillation (ENSO) • Pacific Decadal Oscillation (PDO)

  8. -Seven Snow Study Sites- Chosen for their long climate records . Steamboat Springs Winter Park . . . Breckenridge Aspen . Crested Butte Telluride* Up to 2008 . Valley Coop Sites, Not Ski Areas Silverton

  9. El Niño Southern Oscillation (ENSO) • Simple Definition: variance from normal sea surface temperatures (and sea level pressure and winds) in the eastern equatorial Pacific Ocean. El Niño: a warm change (+ENSO) La Niña: a cold change (-ENSO) • ENSO changes the jet streams (winds aloft) which changes the storm track with resulting predictable effects • ENSO effects are felt mainly in the cold season • ENSO: primary winter outlook tool

  10. El Niño • Dry and Warm North of Colorado • Wet and Cool South of Colorado • La Niña • Wet and Cold North of Colorado • Dry and Warm South of Colorado

  11. La Niña December-January (northern mountains)

  12. ENSO Events Since 1950

  13. ENSO Review ENSO is an important part of long-range national forecasts Colorado precipitation is highly variable and has some (subtle) cold season response to ENSO El Niño produces a wetter spring and fall. El Niño years are wetter for the San Juan mountains and Front Range. La Niña produces a snowier heart of winter, centered on January, favoring the northern mountains.

  14. CPC Forecast Skill Scores for Colorado During Non-ENSO Years 0% Skill!

  15. Pacific Decadal Oscillation • A long-lived ENSO-like pattern in the northern Pacific. • PDO events persist for 20-30 years, while typical ENSO events last for 6-18 months.

  16. Pacific Decadal Oscillation 2007 Warm phase Cool phase

  17. CPC’s Outlook Dec-Jan-Feb 2012-2013 Temperature Precipitation ENSO Neutral

  18. Forecast for 2012-2013 • Colorado Mountain Snow Season • No Niño conditions, and the PDO in cold phase, brings an increased probability of • Seasonal Snowfall Totals: Below Normal. • Details: near normal northwest mountains • snowy December (perhaps extending into November or January but not both) • wet April (valley rain/mountain snow). • An extreme year is quite possible, most likely extremely dry. • Colorado drought will likely persist or worsen.

  19. What Happened Last Season?

  20. Snowfall Totals from Last Season

  21. Current Pacific Conditions:ENSO Neutral and PDO is cold • Neutral ENSO (ONI of -0.4C) • Cold PDO (Index of -1.04C)

  22. Compare the conditions for this season to previous similar seasons with respect to: Neutral ENSO conditions Subsets of ENSO Neutral seasons With an emphasis on the last 15 years (Trends) Cold PDO Does the second ENSO Neutral season in a row behave differently? And what about a wet fall season? Analyzed for Snowfall Only No Direct Temperature Forecast

  23. Pacific Niño 3.4 Region Sea Surface Temperature Outlook El Nino Neutral La Nina

  24. ENSO Neutral Events Since 1950

  25. ENSO Neutral Events Since 1950

  26. ENSO Neutral Events Since 1950

  27. Nineteen No Niño Seasons

  28. ENSO Neutral Events Within the Last 15 Years (Trends)

  29. April 2002 April 2004 Cold PDO April 2013

  30. Previous Seasons Similar to the Upcoming Season No Niño Trends (within the last 15 Years) Two dry years and one semi dry.

  31. ENSO Neutral Trends Seasons

  32. Other ENSO Neutral Sub Groups • Nine ENSO Neutral Seasons with cold PDO • 1961-62 snowy north, dry south • 1962-63 extreme dry at WP, Breckenridge, CButte, Silv • 1966-67 Near normal • 1967-68 Dry • 1978-79 Extremely Dry at 4 of 7 sites • 1989-90 Below Normal except Telluride • 1990-91 Near to Above Normal • 2001-02 Extremely Dry • 2012-13 Near to Below Normal • Results: Mostly Dry with two or three above normal seasons.

  33. ENSO Neutral Seasons with cold PDO

  34. Other ENSO Neutral Sub Groups • Nine ENSO Neutral Seasons Second in a Row • 1960-61 Near Normal • 1961-62 Snowy north, dry south • 1962-63 Extremely Dry at WP Breck CB Silverton • 1967-68 Near Normal • 1979-80 Near Normal • 1980-81 Extreme Dry • 1981-82 Near Normal • 1990-91 Above Normal (Nov-Dec, Mar-Apr) • 1993-94 Overall Dry • Results: Mostly Dry with only one or two above normal seasons.

  35. ENSO Neutral Seasons Second in a Row

  36. Other ENSO Neutral Sub Groups • Seven ENSO Neutral Seasons with a Wet Fall Season • 1961-62 Snowy north, dry south • 1967-68 Near Normal • 1979-80 Near Normal • 1985-86 Below Normal North, Above normal South • 1990-91 Above Normal (Nov-Dec, Mar-Apr) • 2001-02 Extremely Dry • 2003-04 Extremely Dry except Silverton • Results: A Mix of Above, Below and Near Normal Seasons.

  37. ENSO Neutral Seasons with a Wet Fall

  38. Analysis Conclusions • All Neutral ENSO conditions (19) • - Averaged Below Normal Snowfall • ENSO Neutral seasons within the last 15 years (3) • - Averaged Below Normal Snowfall • ENSO Neutral seasons with cold PDO (9) • - Averaged Below Normal Snowfall • ENSO Neutral seasons that were the second in a row (9) • - Averaged Below Normal Snowfall • ENSO Neutral seasons with a wet fall season (7) • - Averaged Below Normal Snowfall. • There are four extreme dry seasons (03-04 01-02 80-81 62-63), only two extremely wet seasons (92-93 96-97).

  39. Forecast for 2013-2014 • Colorado Mountain Snow Season • ENSO Neutral becoming El Niño, and the PDO in cold phase, brings an increased probability of • Seasonal Snowfall Totals: Below Normal. • Details: • snowy November into December • wet March-April (if El Nino develops) favoring southwest mountains. • An extreme year is less likely due to an El Nino spring, but still a threat.

  40. Farmer’s Almanac Dan Moroz’s Woolly Bear Caterpillar

  41. Questions?

More Related